First of all thank you for the honest feedback.
I understand your skepticism. At worst it requires more effort and harms the experience for certain jam games. At best it is a reskin of itch.io randomizer. I could say that the value is in future "plans" but that is not what the app currently is.
The goal behind the app is to make the process of discovering and playing new games as simple as possible. Instead of having to take the time to look for something interesting, a player can simply jump in and get started. Originally the idea was for games to be cut into simple 5 minute intervals that would make it easy for players to play, but as you said unless a developer happens to have a level or section of the game that is simple enough to play without the previous levels and happens to fit within the timespan, it is going to be difficult and time consuming to curate an experience just for a website.
I think you're right that project pages already help a lot with this situation. My issue with that is just the fact that you have to go on itch.io, decide what type of game you want to play, look for an interesting thumbnail, read about the game and controls, rather than jump in. In other words this is app is not meant to replace the current way of discovering games but offering an alternative.
I also agree with what you are saying about the game type playing an important role. I'm really considering removing the time limit (or giving developers the option to have a time limit) as players can easily go to the next game. Generally the more control the developer has over the experience of their game the better I think this app will work.
As for quality my plan is to make this app less of a randomizer and more of an algorithm. I am still working out the details but the idea is to have higher chances for games with good reception or not being discovered compared to games that have been discovered a lot but easily skipped/not liked. To preserve the randomness maybe the weighting will reset after a period of time and allow games a "second chance" for players.
I apologize if this does not fully answer your concerns. Like I said I am doing my best to not just pull a "trust me bro" and spam features that aren't remotely in the app yet. I'm just trying to make the experience a little better for new-coming game developers and players. Again thank you for your time and response.