The infinite grid is a cool idea, but the game as a whole did not feel very engaging. There was no way I was finishing even one full screen of this, which is the bare minimum threshold for getting any value from the infinite grid. I'm not a word search guy, but it feels like the idea might work better with a different puzzle type.

The drag to pan, hold-then-drag to mark felt really clumsy with a mouse. The hold delay is just too long. Maybe consider drag-with-left-button to mark, click/drag-with-right button to pan.

The word list seems odd, half the words I tried were rejected. You don't need many failures to accept a reasonable word to lose faith in the game. Is the idea that only the words at the bottom are in the dictionary? Doesn't feel like it can be, given it only shows about 20 words, is not scrollable in any way I can see, and many words not shown in that list were actually accepted.