In a word, adequate. To be fair, we were in the lowest grade of room (room 10, rather compact). Pricier rooms may be significantly better. There was nothing seriously wrong with it, just lots of little irritations:
* No desk of any kind, just a shelf for tea/coffee making.
* Just one chair, dining-style - we both sat/lay on the bed to watch TV
* Paper-thin walls - useful if you want to know what no.9 is up to in their bathroom.
* Bathroom door handle that creaked enough to wake the dead
* Toilet seat that won't stay up
* No hooks in the bathroom for clothes or damp towels
* Towels on a rack high above the toilet - ok for fresh towels, perhaps, but not damp ones
The included or £7.50 breakfast was about as basic as you'll find. (See photo of menu). Tea/coffee, orange/apple juice, a few cereals, muesli (unsweetened - good - but rather basic), fresh fruit salad (mainly apples and oranges), fruit yoghurt (cheap, UPF variety), toast with salted butter and jams/marmalade. That's it. No berries or seasonal fruit (not even a banana), no croissants or other pastries, not even natural yoghurt. Scrambled/poached eggs were just £2.50 extra. full English another £2.50.
The breakfast room was rather gloomy and lacking in any kind of style or atmosphere, so we chose not to have dinner there. Kings Lynn (town centre a mile's walk via a pleasant park) seems very short of good dining options. Our first evening was a Saturday, so the most promising option, Mem's Kitchen, was fully booked (both branches).
We finished up in the conservatory upstairs at the Crown & Mitre and were pleasantly surprised by the menu and friendly, efficient service. Seafood curry strongly recommended. Not fine dining, of course, but an enjoyable evening.
The second evening, we resorted to Prezzo, which was enjoyable enough, with a good Saltimbocca Chicken and a pleasant malbec. There was a 25% food voucher on the Prezzo website, so the bill was very reasonable.
Parking at the hotel was a bit random, with cars all over the place, but we had no difficulty finding a space. If you drive an EV, there are two 7kW Pod Point chargers - 45p/kWh. For Tesla, though, you'd do better at the superchargers just out of town, 34p/kWh off-peak, 43p peak (4-8 pm). Just be sure to register your reg with the hotel , using a tablet to the left of reception, or expect a £100 fine.