Well the game I wrote is 18 MB all zipped up, and only slightly bigger than that after you install. See if you can do better than that.
Keep in mind it's old school. Not what they call retro today, which has fancy graphics and sounds that we never actually had in the 80s, but what actually is retro, think 1984 style graphics. Game uses only 16 colors and uses NSF for music (Nintendo sound format). There are modern niceties like being able to save/load without restarting your computer :)
Also you mentioned loot, the game doesn't really have a loot system with drops like WoW or Diablo, but there is money and you can buy things at them. There is no grind though, no levels, and buying things is optional but recommended. But there is tactical combat, and your party changes often enough so it is interesting without having to grind XP (though if you want to grind XP, this game is not for you).
Here is a good review of it:
http://indieoverlook.com/2016/04/15/epikos/
Anyway you can check out my website/trailer or my itch.io page