Watching the Bal let Nacional de Cuba is a fascinat ing, strange expe rience, like being in rickety time machine that needs a whack to get started. On opening night Wednesday, some things fell apart, but when they worked, it was a window on ballet as it might have looked half a century ago.

The company, with a live orchestra, is on its first American tour in almost a decade. It’s dancing full ballets in other cities, but a program of snippets here: dances and pas de deux from an entire season’s worth of classics jammed into an evening. The versions are all by the company’s director, legendary ballerina Alicia Alonso, based on what she herself danced in the 1940s.

The costumes and backdrops, made on a shoestring budget, have a tinsel and papier-maché grandeur. The performances have the same contradiction: wonderful but weird, accomplished but nervous. The dancers have legendary training and strength, but like gymnasts, they’re so concerned with sticking their positions that if things go wrong, they actually get stuck.

One of the tricky partnered “fish dives” in “The Sleeping Beauty” went awry, leaving Yanela Pinera splayed upside down on Alfredo Ibanez’s back. But she recovered to do amazing repeated turns.

There were more triumphs of old-school strength and grit. Veteran ballerina Barbara Garcia has a tough, sinewy delicacy — she’s tiny, but could probably pitch you through a window. During “The Nutcracker,” she cranked out balances, staring us down as if to warn us there would be a quiz afterwards.

Even the young dancers looked old-fashioned. Grettel Morejon was lithe and fluid in “Coppelia,” with take-no-prisoners showmanship. As she walked across the stage on pointe, she held out her arms and flirted shamelessly with the front rows, as if beckoning them to join her onstage.

The most promising man was Alejandro Virelles, a tall drink of water whose turns and tricks in “Don Quixote” never budged from a slow-as-molasses pace — but never went askew.

The company closed with Alonso’s “Gottschalk Symphony,” a retro classical finale with the dancers in burgundy velvet doing their favorite tricks to a tropical beat. It was a fitting end to an evening of contradictions.