After taking a peek around, I am strongly considering using this site to sell the various digital products my company makes, but I was wondering if it's possible to use it for more than one thing at a time. Do I have to make separate tiers for each project, or how else do I can make this work?

You can sell tiered items and set up easy tiered payment say you wan to offer one project or game for 5 dollars and another for 10 ect ect then you can upload them all and set the prices as youd like all on one page, weve done this with products offering a cheaper smaller version for those who paid 15 and a larger version for $40 sounds about the same as youd like to do with your products!