Mr. Rogers should immediately contact a patent attorney that specializes in copyright and trademark laws. This is because the phrase
all rights convey to the licensee
means that John Rubrik will have all the control of Mr. Rogers's product. Yet, in a contract, those words must explain whether this is for a specific period of time, or whether Mr. Rogers has basically lost every right to his creation. Therefore, Mr. Rogers can contest to the contract by asking a lawyer to add a clause that may make Mr. Rogers keep some rights to the product, or better yet, to limit the powers of Mr. Rubrik over Rogers's game.
From the generosity of the offer, it seems as if Mr. Rubrik sees the talent of Mr. Rogers as a toy and game designer and wants to keep the talent producing more products that later on will become the property of Mr. Rubrik's company. Now, it is entirely up to Mr. Rogers if he wants to give up the rights to his product; after all, the contract is generous, indeed and Mr. Rogers will have a chance to make future products. For this very reason, it is imperative that a patent lawyer is hired to delineate exactly just how much Mr. Rogers will be able to keep from his own creations, and how much he is willing to lose as far as rights.
Rights are earned through the blood, sweat, or tears of very courageous people so they should never be taken for granted. To give up a right is no different, in the long scheme of things, as giving a large amount of something that may be needed later on; in other words, giving up a right is like giving up oxygen, water, health, food. Therefore, Mr. Rogers should definitely consider giving the contract to a patent lawyer that could represent him as well as his product.