In principle, searching by the exact title should work, but many games have extremely generic titles. Sometimes dozens of games are named essentially the same. (Can't think of an example right now, sorry.) When that happens, a search might surface other games than the expected one.
Tetris. There are at least 123 games named exactly Tetris. What I do not know, if there are more games named Tetris, that did not appear in the search for tetris. It yields 180 items. There are 1600 games tagged tetris, but only 71 of them are named exactly Tetris.
I do know that searches will not give all results of titles containing the word(s). I found two examples created by pop shop.
Maybe it is different for single word searches matching single word titles. Those examples had multiple words and the search was for a subset of the words.