From here:
JFresh x AllThreeZones Microstat Player Cards Explainer
Entries: The number of times a player entered the offensive zone with the puck (either carrying it in, passing it in, or dumping it in). Indicates a player’s workload in entering the zone.
Entry % w/possession: The rate with which a player enters the zone with possession (carrying or passing as opposed to dumping the puck in) relative to his total zone entries. On average, a forward will enter with possession about 55% of the time.
Entry success rate: A player’s rate of success when attempting to enter the offensive zone. On average, a forward will be able to enter the zone in some fashion on 88% of his attempts. Players who are more ambitious with their entries (e.g. trying to go one-on-one instead of dumping it in) might succeed less often.
I think the last definition is kind of important and it probably explains why Kuznetsov's entry success rate is somewhat poor while Hagelin's is pretty good. Kuznetsov rarely dumps it in and as a result his success rate is lower. It'd be nice if they did some sort of weighted average since we know that controlled entries lead to more offense than dump-ins. For example, Connor McDavid only ranks in the 59th percentile in terms of entry success percentage though I think most people would agree he's way better than average at entering the zone. Same with Nathan MacKinnon, who is only in the 40th percentile.