The game includes 132 tiles, specifically two sets of tiles in six colors, with the tiles being numbered 1-11 in each color. Each player starts with eight tiles in hand, and you can discard and redraw once before the game begins. On a turn, you either (1) discard up to four tiles in your hand from the game, then draw that many tiles from the bag or (2) play one or more tiles from your hand to a color on your board, then draw that many tiles. You can play tiles of only one color, and all the tiles played must be equal to or less than any tiles of that color you already have in play. You place these tiles in descending order, and you can build at most six rows during the game, one of each color.
Whenever you want, you can switch to phase two. Once you do this, on a turn you either (1) discard up to four tiles in your hand from the game, then draw that many tiles from the bag or (2) clear tiles from your play area to score them. To do this, choose one or more tiles in your play area of only a single color, starting with the lowest valued tile (or tiles), then sum the tiles you want to score. You must then "pay" to score these tiles by discarding tiles of one color from your hand that sum to this same amount or higher. The tiles you discard from your hand don't have to be the same color as the color of the tiles you're scoring. Remove the tiles you paid from the game, and place the tiles you've cleared face down in a score pile. Refill your hand to eight tiles at the end of your turn.
As soon as someone draws the final tile from the bag, you complete the round so that everyone has had the same number of turns, then the game ends. A player's score equals the sum of the tiles that they've cleared minus the sum of the tiles they still have in play. (Tiles in a player's hand are discarded.) Whoever has the highest score wins!
In feel, No Return bears similarities to Lost Cities and Qwixx, two games in which you must take an action on your turn even though the urge to pass sometimes smothers your desire to do anything else. In all three of these games, you're often confronted with the option to commit in a color, knowing that doing so cuts off potential scoring in everything you're leaping over. Do you play the 4 or 5 in Lost Cities, risking a penalty should no other cards appear in that color, or do you throw it away, instead risking your opponent scooping it up for double or triple points and an eight-card bonus?
Opponents can't grab the tiles that you toss in No Return, but all too often you realize many turns later that you could have just played those tiles to your collection since you never drew any more tiles of that color anyway — yet you couldn't have known that would happen, so was it really a bad play? Maybe it was, but with only eight games experience, I feel like I'm still getting the rhythm of the game, something that will change with each player count since you'll have fewer of the tiles passing through your hands and more tiles visible in play to better let you weigh the odds of which action might be the right one to carry out.
For more on the game, here's a video overview I recorded, which shows the size of the tiles and lets you see that the pink and red colors are too close to one another, a problem that has stymied many publishers in many games:
Update: Despite me describing the game correctly in the description above, when I played the game, I somehow transformed the "discard up to four tiles" rule into a "discard exactly four tiles" rule. Thus, I'm now describing an unintended game variant in the video below. I'll have to get this title back to the table post-SPIEL '19 for more games by the rules...