Many of the top-selling games on itch right now are episodic games that release new content periodically.

But itch.io doesn't  allow players to accumulate their payments for that game over time.

Example:

• Episode 1 → $2
• Episodes 1 and 2 → $4

If a person buys episode 1, and a few days later wants to buy episode, 2 they have to pay a total of $6 ($2 for the first purchase and $4 for the second purchase).

Instead, I suggest that players only need to pay the difference ($2 for the first purchase, and $2 for the second purchase).