I can't give a definitive answer, sorry. People have done this before and weren't asked to stop, so it's probably fine. In fact it's necessary if your game is an MMO, as you'd have to host the game somewhere on a server of your own. It does however come with technical difficulties, but I don't know much about it, so you'll have to contact support like Dark Dimension suggested.
As for the project size, see Dark Dimension's answer again (thanks for the help!) but keep in mind that 1.5G is huge for a browser-based game no matter where it loads from. Most players won't be happy, if they manage to play it at all.