Both are ads, and treating them as interchangeable is how a game with decent numbers becomes a game people uninstall.
Rewarded ads are opt in. The player chooses to watch in exchange for something: a continue, a doubled reward, a hint. Because it is a choice, it does not generally hurt retention, and players who use them often report liking the game more, not less. The design work is placing the offer where the player actually wants the thing.
Interstitials are interruptions. They pay per impression whether or not the player wanted it, so they are tempting. The cost is real but delayed: shown too often, or at the wrong moment, they push people out. The damage does not appear in today's revenue, it appears in next week's retention.
Placement rules that hold up. Never interrupt play. Show at a natural break, after a level ends and before the next begins, and never immediately after a loss, when the player is already frustrated. Never during the first session, before anyone has decided whether they like your game. Cap frequency, and enforce a minimum gap in time as well as a count.
The number to actually watch is not eCPM, it is revenue per user over the first week or two, alongside retention. A configuration that lifts today's revenue and drops day-seven retention is losing you money slowly.
Practical starting shape for a casual game: rewarded ads available generously wherever they make sense, interstitials rare and only at genuine breaks, and no ads at all in the first session.
Test one change at a time. Changing frequency and placement together tells you nothing about which one mattered.
Rewarded ads are opt in. The player chooses to watch in exchange for something: a continue, a doubled reward, a hint. Because it is a choice, it does not generally hurt retention, and players who use them often report liking the game more, not less. The design work is placing the offer where the player actually wants the thing.
Interstitials are interruptions. They pay per impression whether or not the player wanted it, so they are tempting. The cost is real but delayed: shown too often, or at the wrong moment, they push people out. The damage does not appear in today's revenue, it appears in next week's retention.
Placement rules that hold up. Never interrupt play. Show at a natural break, after a level ends and before the next begins, and never immediately after a loss, when the player is already frustrated. Never during the first session, before anyone has decided whether they like your game. Cap frequency, and enforce a minimum gap in time as well as a count.
The number to actually watch is not eCPM, it is revenue per user over the first week or two, alongside retention. A configuration that lifts today's revenue and drops day-seven retention is losing you money slowly.
Practical starting shape for a casual game: rewarded ads available generously wherever they make sense, interstitials rare and only at genuine breaks, and no ads at all in the first session.
Test one change at a time. Changing frequency and placement together tells you nothing about which one mattered.