The upgrades do seem pretty straightforward as far as wording, but I didn't fully understand how some of the "spirit" ones worked, so I might look it up elsewhere before I play again. I just bought the "recommended" items, but I also kept getting demolished, so maybe I need to branch out.

It's not too daunting. It has the same guide system as dota so you can just pick a build someone else made and follow it to learn them. It also has a lot of voice lines to help with reacting to item effects, like the item with an active that makes you invulnerable to bullets makes heroes say a "I can't shoot them" or "don't waste your ammo" voice line.