INCREMENTAL FACILITY AMENDMENT TO CREDIT AGREEMENT

Exhibit 99.1

INCREMENTAL FACILITY AMENDMENT TO CREDIT AGREEMENT

INCREMENTAL FACILITY AMENDMENT, dated as of September 26, 2009 (this “ Amendment ”), to the Credit Agreement, dated as of January 28, 2008 and amended by that certain Amendment and Waiver dated as of June 3, 2009 (as amended, amended and restated, modified or supplemented from time to time, the “ Credit Agreement ”), among Harrah’s Operating Company, Inc., a Delaware corporation (the “ Borrower ”), Hamlet Merger Inc., a Delaware corporation (“ Holdings ,” which was merged on January 28, 2008 with and into Harrah’s Entertainment, Inc.), the lenders from time to time party thereto (the “ Lenders ”), Bank of America, N.A., as administrative agent and collateral agent (in such capacity, the “ Administrative Agent ”), and the other parties named therein.

W I T N E S S E T H:

WHEREAS, the Borrower has requested that the Incremental Lenders (as defined below) provide Incremental Term Loans pursuant to Section 2.21 of the Credit Agreement in the form of Other Term Loans in an aggregate principal amount of $1,000,000,000.

WHEREAS, the Incremental Lenders are willing to provide such Incremental Term Loans to the Borrower pursuant to the terms and subject to the conditions set forth herein.

WHEREAS, with respect to such Incremental Term Loans, (x) Banc of America Securities LLC (“ BAS ”) and Citigroup Global Markets Inc. (“ CGMI ”) will act as the joint lead arrangers, (y) BAS, CGMI, Credit Suisse Securities (USA) LLC (“ Credit Suisse ”), Deutsche Bank Securities Inc. (“ DBSI ”) and J.P. Morgan Securities Inc. (“ JPMorgan ”) will act as the joint bookrunners, and (z) Goldman Sachs Credit Partners L.P. (“ GSCP ”) and Morgan Stanley Senior Funding, Inc. (“ MSSF ,” and together with BAS, CGMI, Credit Suisse, DBSI, JPMorgan and GSCP, the “ Incremental Arranging Parties ”) will act as co-managers.

NOW, THEREFORE, in consideration of the premises and covenants contained herein and for other good and valuable consideration, the receipt and sufficiency of which are hereby acknowledged, the parties hereto, intending to be legally bound hereby, agree as follows:

ARTICLE I

Definitions

Section 1.1. Defined Terms. Terms defined in the Credit Agreement and used herein shall have the meanings given to them in the Credit Agreement unless otherwise defined herein or the context otherwise requires. As used in this Amendment, the following terms have the meanings specified below.

“ Amendment Transactions ” shall mean the execution and delivery of this Amendment and the Reaffirmation Agreement (as defined in Section 4.1(f) hereof) by each Person party hereto or thereto, the satisfaction of the conditions to the effectiveness hereof and thereof and the consummation of the transactions contemplated hereby and thereby.

“ Fee Letter ” shall mean the Fee Letter dated September 26, 2009, by and among the Borrower, the Incremental Arranging Parties and the other parties party thereto.

“ Incremental Lenders ” shall mean the persons listed on Schedule 1 hereto (other than any such person that has ceased to be a party hereto pursuant to an Assignment and Acceptance in

accordance with Section 9.04 of the Credit Agreement), as well as any person that becomes an “Incremental Lender” hereunder pursuant to Section 9.04 of the Credit Agreement.

“ Incremental Effective Date ” shall mean the date on which all the conditions set forth or referred to in Section 4.1 hereof shall have been satisfied (or waived by each of the Incremental Lenders).

“ Term B-4 Loan Commitment ” shall mean, with respect to each Incremental Lender, the commitment of such Incremental Lender to make Term B-4 Loans hereunder on the Incremental Effective Date. The principal amount of each Incremental Lender’s Term B-4 Loan Commitment is set forth on Schedule 1 hereto, or in the Assignment and Acceptance pursuant to which such Incremental Lender shall have assumed its Term B-4 Loan Commitment, as applicable. The aggregate amount of the Term B-4 Loan Commitments of all Incremental Lenders as of the date of this Amendment is $1,000,000,000.

“ Term B-4 Loans ” shall mean the loans made pursuant to Section 2.1 of this Amendment.

“ Ticking Fee” shall have the meaning assigned to such term in Section 4.2 of this Amendment.

ARTICLE II

Commitment

Section 2.1. Commitment. Subject to the terms and conditions set forth herein, each Incremental Lender agrees to make Term B-4 Loans to the Borrower on the Incremental Effective Date in a principal amount not to exceed such Incremental Lender’s Term B-4 Loan Commitment in accordance with the applicable procedures set forth in Article II of the Credit Agreement. The Borrower agrees to pay to each Incremental Lender on the Incremental Effective Date a closing fee equal to 2.50% (the “ Closing Fee ”) of such Incremental Lender’s Term B-4 Loan made on the Incremental Effective Date. Such Closing Fee will be in all respects fully earned, due and payable on the Incremental Effective Date and nonrefundable and non-creditable thereafter. The Borrower authorizes each such Incremental Lender to satisfy the Borrower’s obligation to pay such Closing Fee to such Incremental Lender by such Incremental Lender deducting the amount of such Closing Fee from the principal amount of the Term B-4 Loan disbursed on the Incremental Effective Date by such Incremental Lender and by such Incremental Lender retaining the amount so deducted for such Incremental Lender’s own account. The payment of such Closing Fee shall not reduce the principal amount of the Term B-4 Loan made by such Incremental Lender, and the disbursement of the proceeds of such Term B-4 Loan, exclusive of the amount of such Closing Fee, shall satisfy such Incremental Lender’s Term B-4 Loan Commitment relating thereto in full. Unless previously terminated, the Term B-4 Loan Commitments shall terminate at 5:00 p.m., New York City time, on the earlier of (x) the Incremental Effective Date and (y) November 13, 2009.

ARTICLE III

Amendments

Effective as of and subject to the occurrence of the Incremental Effective Date:

Section 3.1. Amendments to Section 1.01.

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(a) Section 1.1 of the Credit Agreement is hereby amended by inserting the following definitions in proper alphabetical order:

“ Incremental Amendment ” shall mean the Incremental Facility Amendment, dated as of September 26, 2009, among the Borrower, Holdings, the Incremental Lenders party thereto and the Administrative Agent.

“ Incremental Effective Date ” shall have the meaning assigned to such term in Section 1.1 of the Incremental Amendment.

“ Repaid Term B-4 Loans ” shall have the meaning assigned to such term in Section 2.11(a)(iv).

“ Term B-4 Applicable Premium ” shall mean, as of any date upon which a prepayment is payable pursuant to Section 2.11(a)(iv), the present value at such date, computed using a discount rate equal to the Term B-4 Treasury Rate plus 50 basis points, of the sum of (x) the prepayment premium that would be payable on October 15, 2011 with respect to the applicable Repaid Term B-4 Loans plus (y) all interest that would accrue (assuming the Borrower had selected consecutive three-month Interest Periods) on the applicable Repaid Term B-4 Loans from such date to October 15, 2011, computed using an interest rate for the Repaid Term B-4 Loans equal to the sum of (i) the greater of (x) the Eurocurrency Rate for an Interest Period of three months commencing on such date and (y) 2.0% plus (ii) the Applicable Margin in effect on such date for Term B-4 Loans that are Eurocurrency Term Loans.

“ Term B-4 Borrowing ” shall mean a Borrowing comprised of Term B-4 Loans.

“ Term B-4 Facility ” shall mean the Term B-4 Loan Commitments and the Term B-4 Loans made pursuant to Section 2.1 of the Incremental Amendment.

“ Term B-4 Facility Maturity Date ” shall mean October 31, 2016.

“ Term B-4 Loan Commitment ” shall have the meaning assigned to such term in Section 1.1 of the Incremental Amendment.

“ Term B-4 Loan Installment Date ” shall have the meaning assigned to such term in Section 2.10(a)(iv).

“ Term B-4 Loans ” shall have the meaning assigned to such term in Section 1.1 of the Incremental Amendment.

“ Term B-4 Treasury Rate ” shall mean, at any date, the yield to maturity as of such date of United States Treasury securities with a constant maturity (as compiled and published in the most recent Federal Reserve Statistical Release H.15 (519) that has become publicly available at least two Business Days prior to such date (or, if such Statistical Release is no longer published, any publicly available source of similar market data)) most nearly equal to the period from such date to October 15, 2011; provided, however, that if the period from such date to October 15, 2011 is less than one year, the weekly average yield on actually traded United States Treasury securities adjusted to a constant maturity of one year will be used.

(b) The definition of “ Applicable Margin ” in Section 1.1 of the Credit Agreement is hereby amended by (i) inserting the text “and (iv) with respect to any Term B-4 Loan, 7.50% per annum in the case of any Eurocurrency Loan and 6.50% per annum in the case of any ABR Loan” immediately

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following clause (iii) in such definition, (ii) replacing the text “and” immediately preceding the text “(iii)” set forth therein with a comma and (iii) inserting the text “(other than Term B-4 Loans)” immediately after the last occurrence of the word “Loans” in such definition.

(c) The definition of “ Class ” in Section 1.1 of the Credit Agreement is hereby amended by inserting the text “Term B-4 Loans,” immediately following the occurrence of the text “Term B-3 Loans,” set forth therein and is hereby further amended by inserting the text “a Term B-4 Loan Commitment,” immediately following the occurrence of the text “a Term B-3 Loan Commitment,” set forth therein.

(d) The definition of “ Commitments ” in Section 1.1 of the Credit Agreement is hereby amended by inserting the text “(including, without limitation, any Term B-4 Loan Commitment)” immediately following the occurrence of the text “Incremental Term Loan Commitment” set forth therein.

(e) The definition of “ Facility ” in Section 1.1 of the Credit Agreement is hereby amended by inserting the text “including, without limitation, the Term B-4 Facility” immediately at the end of such definition.

(f) The definition of “ First Lien Net Proceeds Prepayment Offer ” in Section 1.1 of the Credit Agreement is hereby amended by (x) inserting the text “and/or Term B-4 Loans” immediately after the occurrence of the phrase “Term B-3 Loans” set forth therein and (y) replacing the text “(ii) through (iv)” set forth therein with the text “(ii), (iii), (iv) and (vi)”.

(g) The definition of “ Incremental Term Loan Installment Date ” is hereby amended by replacing the text “(iv)” set forth therein with the text “(v)”.

(h) The definition of “ Incremental Term Loans ” in Section 1.1 of the Credit Agreement is hereby amended by deleting the text “and” immediately preceding the text “Term B-3 Loans” set forth therein and inserting the text “and Term B-4 Loans” immediately following the occurrence of the text “Term B-3 Loans” set forth therein.

(i) The definition of “ Loans ” in Section 1.1 of the Credit Agreement is hereby amended by replacing the phrase “(if any)” with “(including, without limitation, Term B-4 Loans)”.

(j) The definition of “ Term Borrowing ” in Section 1.1 of the Credit Agreement is hereby amended by inserting the text “(including any Term B-4 Borrowing)” immediately following the occurrence of the text “Incremental Term Borrowing” set forth therein.

(k) The definition of “ Term Facility ” in Section 1.1 of the Credit Agreement is hereby amended by inserting the text “, Term B-4 Facility” immediately following the occurrence of the text “Term B-3 Facility” set forth therein.

(l) The definition of “ Term Loan Installment Date ” in Section 1.1 of the Credit Agreement is hereby amended by inserting the text “, Term B-4 Loan Installment Date” immediately following the occurrence of the text “Term B-3 Loan Installment Date” set forth therein and inserting the word “other” immediately prior to the text “Incremental Term Loan Installment Date” set forth therein.

(m) The definition of “ Term Loans ” in Section 1.1 of the Credit Agreement is hereby amended by inserting the text “(including, without limitation, the Term B-4 Loans)” immediately following the occurrence of the text “Incremental Term Loans” set forth therein.

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Section 3.2. Amendments to Section 2.03. Section 2.03(i) of the Credit Agreement is hereby amended by inserting the text “, Term B-4 Loans” immediately following the occurrence of the text “Term B-3 Loans” set forth therein.

Section 3.3. Amendments to Section 2.10.

(a) Section 2.10(a) of the Credit Agreement is hereby amended by (i) renumbering the existing clause “(iv)” as clause “(v)”, (ii) renumbering the existing clause “(v)” as clause “(vi)” and (iii) inserting the following new clause as clause (iv) in such Section:

“(iv) the Borrower shall repay Term B-4 Borrowings on each date set forth below or, if such date is not a Business Day, the next preceding Business Day (each such date being referred to as a “ Term B-4 Loan Installment Date ”), in the aggregate principal amount equal to the amount set forth opposite such Term B-4 Loan Installment Date:

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(b) Section 2.10(a) of the Credit Agreement is hereby further amended by (x) deleting the text “and” at the end of clause (v), (y) replacing the period at the end of clause (vi) with the text “; and” and (z) inserting the following clause as a new clause (vii):

“(vii) to the extent not previously paid, outstanding Term B-4 Loans shall be due and payable on the Term B-4 Facility Maturity Date.”

(c) Section 2.10(c)(iii) of the Credit Agreement is hereby amended by inserting the text “or Term B-4 Loans” immediately after the first occurrence of “Term B-3 Loans” set forth therein and by inserting the text “or Term B-4 Loans, respectively,” after the second occurrence of “Term B-3 Loans” set forth therein.

Section 3.4. Amendments to Section 2.11.

(a) Section 2.11(a)(i) of the Credit Agreement is hereby amended by deleting the text “(except as provided in clauses (ii) and (iii) of this Section 2.11(a)” and replacing it with the following text:

“(except as provided in clauses (ii), (iii) and (iv) of this Section 2.11(a)”

(b) Section 2.11(a) of the Credit Agreement is hereby amended by inserting the following new clause as clause (iv) at the end of such Section:

“(iv) In the event that any Term B-4 Loans are repaid (other than pursuant to Section 2.11(g) or (h) or pursuant to a Permitted Loan Purchase) or any Term B-4 Loans are assigned pursuant to Section 2.19(c) in connection with an amendment to this Section 2.11(a)(iv) or the definition of Term B-4 Applicable Premium (the “ Repaid Term B-4 Loans ”) prior to October 15, 2013 in whole or in part (other than pursuant to Section 2.10(a) or Section 2.11(c)), the Borrower shall pay to the Lenders having such Repaid Term B-4 Loans a prepayment premium equal to:

(A) if the date of such prepayment or assignment occurs after the Incremental Effective Date but prior to October 15, 2011, the Term B-4 Applicable Premium as of the date of such prepayment or assignment, provided that prior to October 15, 2011, the Borrower may, at its option, on one or more occasions, repay up to 35% of the aggregate principal amount of the Term B-4 Loans subject to a prepayment premium on the principal amount of Term B-4 Loans being prepaid equal to the sum of (i) the greater of (x) the Eurocurrency Rate for an interest period of three months commencing on such date and (y) 2.0% plus (ii) the Applicable Margin for Term B-4 Loans that are Eurocurrency Term Loans in effect on such date, plus accrued and unpaid interest thereon to the date of such repayment, with the net cash proceeds of one or more offerings of Qualified Equity Interests, provided that (x) at least 50% of the original aggregate principal amount of Term B-4 Loans remains outstanding immediately after the occurrence of each such repayment and (y) each such repayment occurs within 90 days of the date of receipt of the equity proceeds so utilized,

(B) 5.0%, if the date of such prepayment or assignment occurs after October 15, 2011 but prior to October 15, 2012, and

(C) 3.0%, if the date of such prepayment or assignment occurs after October 15, 2012 but prior to October 15, 2013.

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(c) Section 2.11(h)(i) of the Credit Agreement is hereby amended by (i) deleting the text “(other than Term B-3 Loans)” from clause (y) of such Section and replacing it with the text “(other than Term B-3 Loans and Term B-4 Loans)” and (ii) inserting the text “and, subject to clause (vi) of this Section 2.11(h), Term B-4 Loans” immediately after the text “Term B-3 Loans” in clause (z) of such Section.

(d) Section 2.11(h)(ii) of the Credit Agreement is hereby amended by inserting the text “and the Applicable Facility Percentage for the Te